check_hresult returns the hresult as a convenience #971
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Like `check_pointer`, `check_hresult` accepts multiple successful
values. The `check_pointer` function returns the successful pointer,
but `check_hresult` had swallowed it, which made using `check_hresult`
inconvenient when interoperating with things like COM enumerators that
use `S_FALSE`. For example:
```cpp
com_ptr<IShellItem> item[1];
hresult error;
while (check_hresult(error = e->Next(1, item[0].put(), nullptr)), error == S_OK)
{
do_stuff(item);
item[0] = nullptr; // prepare for next iteration
}
```
Letting `check_hresult` return the `hresult` simplifies the code:
```cpp
com_ptr<IShellItem> item[1];
while (check_hresult(e->Next(1, item[0].put(), nullptr)) == S_OK)
{
do_stuff(item);
item[0] = nullptr; // prepare for next iteration
}
```
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Like
check_pointer,check_hresultaccepts multiple successful values. Thecheck_pointerfunction returns the successful pointer, butcheck_hresultswallows the successful result, which makes usingcheck_hresultinconvenient to use with COM methods that returnS_FALSE. For example:Extending
check_hresultto return the successfulhresultsimplifies the code:I think it is unlikely that anybody has been doing
decltype(check_hresult()), so changing the return value should be non-breaking.